<div class="case">
  <!-- First row -->
  <div class="key" data-key="escape">esc</div>
  <div class="key" data-key="1"></div>
  <div class="key" data-key="2"></div>
  <div class="key" data-key="3"></div>
  <div class="key" data-key="4"></div>
  <div class="key" data-key="5"></div>
  <div class="key" data-key="6"></div>
  <div class="key" data-key="7"></div>
  <div class="key" data-key="8"></div>
  <div class="key" data-key="9"></div>
  <div class="key" data-key="0"></div>
  <div class="key" data-key="-"></div>
  <div class="key" data-key="="></div>
  <div class="key xxl" data-key="backspace"></div>
  <div class="key" data-key="help">ins</div>
  <div class="key" data-key="home"></div>
  <!-- Second row -->
  <div class="key large" data-key="tab"></div>
  <div class="key" data-key="q"></div>
  <div class="key" data-key="w"></div>
  <div class="key" data-key="e"></div>
  <div class="key" data-key="r"></div>
  <div class="key" data-key="t"></div>
  <div class="key" data-key="y"></div>
  <div class="key" data-key="u"></div>
  <div class="key" data-key="i"></div>
  <div class="key" data-key="o"></div>
  <div class="key" data-key="p"></div>
  <div class="key" data-key="["></div>
  <div class="key" data-key="]"></div>
  <div class="key large" data-key="\"></div>
  <div class="key" data-key="delete">del</div>
  <div class="key" data-key="end"></div>
  <!-- Third row -->
  <div class="key xl" data-key="capslock">caps</div>
  <div class="key" data-key="a"></div>
  <div class="key" data-key="s"></div>
  <div class="key" data-key="d"></div>
  <div class="key" data-key="f"></div>
  <div class="key" data-key="g"></div>
  <div class="key" data-key="h"></div>
  <div class="key" data-key="j"></div>
  <div class="key" data-key="k"></div>
  <div class="key" data-key="l"></div>
  <div class="key" data-key=";"></div>
  <div class="key" data-key="'"></div>
  <div class="key xl" data-key="enter">return</div>
  <div class="key" data-key="f15">pause</div>
  <div class="key" data-key="pageup">pg up</div>
  <!-- Fourth row -->
  <div class="key xxl" data-key="shiftleft">shift</div>
  <div class="key" data-key="z"></div>
  <div class="key" data-key="x"></div>
  <div class="key" data-key="c"></div>
  <div class="key" data-key="v"></div>
  <div class="key" data-key="b"></div>
  <div class="key" data-key="n"></div>
  <div class="key" data-key="m"></div>
  <div class="key" data-key=","></div>
  <div class="key" data-key="."></div>
  <div class="key" data-key="/"></div>
  <div class="key xxl" data-key="shiftright">shift</div>
  <div class="key" data-key="arrowup">▲</div>
  <div class="key" data-key="pagedown">pg dn</div>
  <!-- Fifth row -->
  <div class="key medium" data-key="controlleft">ctrl</div>
  <div class="key medium" data-key="meta">win</div>
  <div class="key medium" data-key="altleft">alt</div>
  <div class="key huge" data-key=" "></div>
  <div class="key medium" data-key="altright">alt</div>
  <div class="key medium" data-key="fn"></div>
  <div class="key medium" data-key="controlright">ctrl</div>
  <div class="key" data-key="arrowleft">◀</div>
  <div class="key" data-key="arrowdown">▼</div>
  <div class="key" data-key="arrowright">▶</div>
</div>

body {
  background-color: #625499;
  display: table-cell;
  height: 100vh;
  margin: 0;
  text-align: center;
  vertical-align: middle;
  width: 100vw;
}

.case {
  background-color: #463973;
  border-color: #2e2640;
  border-radius: 5px;
  border-style: solid;
  border-width: 8px 10px 15px 10px;
  display: inline-grid;
  grid-template-columns: repeat(36, 1fr);
  grid-template-rows: repeat(5, 1fr);
  height: 17em;
  padding: 5px;
  user-select: none;
  width: 60em;
}

.key {
  border-color: #382e59 #2e2640;
  border-radius: 2px;
  border-style: solid;
  border-width: 3px 5px 8px 5px;
  color: #bbadd9;
  display: block;
  font-family: sans-serif;
  font-size: 9px;
  font-weight: 800;
  grid-column-end: span 2;
  margin: 3px;
  padding-top: 2px;
  padding: 5px;
  text-align: center;
  text-transform: uppercase;
  transition: all 50ms ease-out;
  will-change: box-shadow, color, text-shadow;
}

.key:empty::before {
  content: attr(data-key);
}

.active {
  transform: perspective(1200px) translateZ(-90px);
}

.medium {
  grid-column-end: span 3;
}

.large {
  grid-column-end: span 4;
}

.xl {
  grid-column-end: span 5;
}

.xxl {
  grid-column-end: span 6;
}

.xxxl {
  grid-column-end: 7;
}

.huge {
  grid-column-end: span 12;
}

const keysArr = [...document.querySelectorAll(".key")];

const getKey = (event) => {
  const parsedKey = event.key.toLowerCase().replace("\\", "\\\\");
  const parsedCode = event.code.toLowerCase();
  const element =
    document.querySelector(`[data-key="${parsedCode}"]`) ||
    document.querySelector(`[data-key="${parsedKey}"]`);

  return element;
};

document.addEventListener("keydown", (event) => {
  const key = getKey(event);
  if (key) {
    key.classList.add("active");
  }
});

document.addEventListener("keyup", (event) => {
  const key = getKey(event);
  if (key) {
    key.classList.remove("active");
  }
});

document.addEventListener("mousedown", (event) => {
  if (event.target.dataset.key) {
    event.target.classList.add("active");
  }
});

document.addEventListener("mouseup", (event) => {
  if (event.target.dataset.key) {
    event.target.classList.remove("active");
  }
});

document.addEventListener("touchstart", (event) => {
  if (event.target.dataset.key) {
    event.target.classList.add("active");
  }
});

document.addEventListener("touchend", (event) => {
  if (event.target.dataset.key) {
    event.target.classList.remove("active");
  }
});

const animate = (element) => {
  const hueColor = Math.floor(Math.random() * (360 - 0 + 1)) + 0;
  const color = `hsla(${hueColor}, 100%, 50%, 50%)`;
  const textColor = `hsl(${hueColor}, 100%, 50%)`;
  const textShadow = `0 0 0.80em ${color}, 0 0 1.60em ${color}, 0 0 4em ${color}`;
  const boxShadow = `-3px 3px 4px ${color}, 3px -3px 4px ${color}, 3px 3px 4px ${color}, -3px -3px 4px ${color}, 0 0 10px ${color}`;

  const keyIndex = keysArr.indexOf(element);
  const animatedKeysRight = keysArr.slice(keyIndex);
  const animatedKeysLeft = keysArr.slice(0, keyIndex);

  const transitionHandler = (event) => {
    event.target.style.boxShadow = "none";
    event.target.style.color = null;
    event.target.style.textShadow = "none";
    event.target.removeEventListener("transitionend", transitionHandler);
  };

  animatedKeysRight.forEach((keyEl, i) => {
    setTimeout(() => {
      keyEl.addEventListener("transitionend", transitionHandler);
      keyEl.style.boxShadow = boxShadow;
      keyEl.style.color = textColor;
      keyEl.style.textShadow = textShadow;
    }, i * 35);
  });

  animatedKeysLeft.forEach((keyEl, j) => {
    const i = animatedKeysLeft.length - j;
    setTimeout(() => {
      keyEl.addEventListener("transitionend", transitionHandler);
      keyEl.style.boxShadow = boxShadow;
      keyEl.style.color = textColor;
      keyEl.style.textShadow = textShadow;
    }, i * 35);
  });
};

document.addEventListener("keydown", (event) => {
  const key = getKey(event);

  if (key) {
    animate(key);
  }
});

document.addEventListener("click", (event) => {
  if (event.target.dataset.key) {
    animate(event.target);
  }
});

window.addEventListener("load", () => {
  const key = document.querySelector(`[data-key="enter"]`);
  animate(key);
});